Impact/Purpose:

The objective of PEMS is to utilize state-of-the-art portable emissions measurement systems for on-vehicle emissions measurements. EPA is interested in measuring actual emission levels as on-highway and non-road vehicles operate in the real world -- performing their normal duties in their normal operating environments. The intended uses of PEMS include data collection for the purpose of populating emissions factor databases, and on-vehicle compliance testing to ensure that in-use vehicles are emitting pollutants as expected. Both ASD and CCD staff will be using these instruments to perform their modelling and compliance activities respectively. PEMS is and will continue to be deployed on on-highway and non-road vehicles in various programs that require on-vehicle emissions data.

Description:

PEMS is a generic term that encompasses all portable emissions measurement systems. Two EPA-developed examples are ROVER (Real-time On-Vehicle Emissions Reporter) for on-highway applications, and SPOT (Simple Portable On-vehicle Tester) for non-road applications. Now, however, several commercial instrument manufacturers offer complete systems, and EPA has begun migrating to these new systems. EPA currently has two Semtech-Ds (for Diesel applications) and two Semtech-Gs (for gasoline applications) manufactured by Sensors, Inc. (Saline, MI). All of them measure only gaseous emissions, however. Therefore, EPA's other focus with PEMS is to currently fund the development of a PEMS device that will measure particulate matter (PM) emissions.

Record Details: